Response of machining-damaged single-crystalline silicon wafers to nanosecond pulsed laser irradiation

Ultraprecision diamond-machined silicon wafers have been irradiated by a nanosecond pulsed Nd:YAG laser. The results indicate that at specific laser energy intensity levels, the machining-induced subsurface damage layer of silicon has been reconstructed to a perfect single-crystalline structure identical to the bulk. Laser irradiation causes two effects on silicon: one is the epitaxial regrowth of the near-surface amorphous layer, and the other is the complete removal of the dislocations from the crystalline layer. It is the dislocation-free crystalline region that serves as the seed layer to recrystallize the amorphous layer, enabling excellent crystalline perfection. These findings may offer practical alternatives to current chemo-mechanical processing methods for silicon wafers.